[108] RAM: RAM content cannot be trusted upon waking up from System ON Idle or System OFF mode

This anomaly applies to IC Rev. Rev 1, build codes QFAA-B00, QFAB-B00, CIAA-B00.

It was inherited from the previous IC revision Engineering C.

Symptoms

RAM not correctly retained.

Conditions

System ON Idle mode or System OFF is used with parts or all RAM retained.

Consequences

RAM not correctly retained.

Workaround

Apply the following code after any reset:
*(volatile uint32_t *)0x40000EE4 = (*(volatile uint32_t *)0x10000258 & 0x0000004F);
This workaround is implemented in MDK version 8.9.0 and newer version. This workaround increases the I_RAM current per 4 KB section from 20nA to 30nA.

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